Browsing by Author "Lee, Shyh-Yuan"

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Automated Segmentation of Dental Calculus in Optical Coherence Tomography Images
(2018-01-01)
Lee, Chia-Yen
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Chuang, Ching-Cheng
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Chen, Guan-Jie
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Huang, Chih-Chia
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Lee, Shyh-Yuan
The presence of dental calculus is highly correlated with the formation and advancement of periodontal disease. The occurrence and relapse of periodontal disease can be prevented only if dental calculus is completely removed. In this study, optical coherence tomography (OCT) is used to obtain two-dimensional cross-sectional images of tooth samples, in conjunction with a segmentation technique that enables automatic identification of dental calculus. We propose the vertical intensity transform function to correct the nonuniform instrument signal intensity caused by OCT. Afterwards, the detection ranges are defined by K-means or the Markov random field (MRF), and the candidate range is selected on the basis of mathematical morphology (MM). Finally, the features (thickness gradient, texture, and tooth surface slope) are quantified, and dental calculus is recognized and segmented. In the preliminary result, the sensitivity is 87.5%. The mean distance between the boundaries generated by the proposed algorithm and the corresponding manually delineated boundaries is 2.52 +/- 3.54 pixels. Our proposed algorithm assists physicians to determine dental calculus more easily. Doctors no longer need to rely solely on their experiences to recognize dental calculus, but can refer to specific data to assist in diagnosis.
Characterization of tooth structure and the dentin-enamel zone based on the Stokes-Mueller calculation
(2012-11-01)
Sun, Chia-Wei
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Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Jiang, Cho-Pei
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Chuang, Ching-Cheng
This is the first study of dentin-enamel zone (DEZ) identification with tooth structure characterization based on the optical Stokes-Mueller measurement. Stokes vectors of a cross-sectional tooth slice were measured using various polarization inputs. The direction of the DEZ is different in enamel and dentin structures; therefore, the Stokes profiles can specifically characterize the structures based on the DEZ. This optical method, using polarimetry, provides a useful tool for characterizing tooth. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.11.116026]
Dental Calculus Image Based on Optical Coherence Tomography
(2011)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Chuang, Ching-Cheng
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Wang, Chun-Yang
In this study, the dental calculus was characterized and imaged by means of swept-source optical coherence tomography (SSOCT). The refractive indices of enamel, dentin, cementum and calculus were measured as 1.625+/-0.024, 1.534+/-0.029, 1.570+/-0.021 and 1.896+/-0.085, respectively. The dental calculus lead strong scattering property and thus the region can be identified under enamel with SSOCT imaging. An extracted human tooth with calculus was covered by gingiva tissue as in vitro sample for SSOCT imaging.
Dental Optical Coherence Tomography
(2013-07-01)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Chuang, Ching-Cheng
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Tsai, Jui-che
This review paper describes the applications of dental optical coherence tomography (OCT) in oral tissue images, caries, periodontal disease and oral cancer. The background of OCT, including basic theory, system setup, light sources, spatial resolution and system limitations, is provided. The comparisons between OCT and other clinical oral diagnostic methods are also discussed.
Optical Polarimetric Detection for Dental Hard Tissue Diseases Characterization
(2019-11-01)
Hsiao, Tien-Yu
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Lee, Shyh-Yuan
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Sun, Chia-Wei
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交大名義發表
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National Chiao Tung University
Dental enamel constitutes the outer layer of a crown of teeth and grows nearly parallel. This unique nanostructure makes enamel possess birefringence properties. Currently, there is still no appropriate clinical solution to examine dental hard tissue diseases. Therefore, we developed an optical polarization imaging system for diagnosing dental calculus, caries, and cracked tooth syndrome. By obtaining Stokes signals reflected from samples, Mueller images were constructed and analyzed using Lu-Chipman decomposition. The results showed that diattenuation and linear retardance images can distinguish abnormal tissues. Our result also aligns with previous studies assessed by other methods. Polarimetric imaging is promising for real-time diagnosing.
Review: Optical Scanning Probe for Optical Coherence Tomography
(2014)
Sun, Chia-Wei
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Lee, Shyh-Yuan
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Lin, Kun-Feng
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光電工程學系
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Department of Photonics
Optical coherence tomography (OCT) has become an important medical imaging modality. However, low penetration depth limits its application. Therefore, the optical scanning probe plays an important role in OCT systems for clinical applications. This article reviews OCT methodology and the mechanisms of an optical scanning probe. Recent developments of OCT probe and related clinical applications are summerized. Various OCT probe techniques (e.g., side imaging and forward imaging) have been used for measuring optical biopsy of various tissues. OCT probes for early diagnosis applications should be developed and combined with functional OCT modalities, such as Doppler OCT and polarization-sensitive OCT, to provide more information for diagnosis.
Sensing of Tooth Microleakage Based on Dental Optical Coherence Tomography
(2015-01-01)
Sun, Chia-Wei
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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影像與生醫光電研究所
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Institute of Imaging and Biomedical Photonics
This study describes microleakage sensing based on swept-source optical coherence tomography (SS-OCT). With a handheld scanning probe, the SS-OCT system can provide portable real-time imaging for clinical diagnosis. Radiography is the traditional clinical imaging instrument used for dentistry; however, it does not provide good contrast images between filling material and the enamel of treated teeth with microleakage. The results of this study show that microleakage can be detected with oral probing using SS-OCT in vivo. The calculated microleakage length was 401 mu m and the width is 148 mu m, which is consistent with the related histological biopsy measurements. The diagnosis of microleakage in teeth could be useful for prevention of secondary caries in the clinical treatment plans developed in the field of oral medicine.
Subgingival calculus imaging based on swept-source optical coherence tomography
(2011-07-01)
Hsieh, Yao-Sheng
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Ho, Yi-Ching
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Lee, Shyh-Yuan
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Lu, Chih-Wei
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Jiang, Cho-Pei
We characterized and imaged dental calculus using swept-source optical coherence tomography (SS-OCT). The refractive indices of enamel, dentin, cementum, and calculus were measured as 1.625 +/- 0.024, 1.534 +/- 0.029, 1.570 +/- 0.021, and 2.097 +/- 0.094, respectively. Dental calculus leads strong scattering properties, and thus, the region can be identified from enamel with SS-OCT imaging. An extracted human tooth with calculus is covered with gingiva tissue as an in vitro sample for tomographic imaging. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3602851]